From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43F79C4361B for ; Tue, 15 Dec 2020 03:13:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E8C1223E0 for ; Tue, 15 Dec 2020 03:13:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726665AbgLODNB (ORCPT ); Mon, 14 Dec 2020 22:13:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:36572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728030AbgLODMu (ORCPT ); Mon, 14 Dec 2020 22:12:50 -0500 Date: Mon, 14 Dec 2020 19:11:25 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608001886; bh=V9+DVml/NeWf8gUp5R7GUgu+kMkY0cbIf9kmYcKKVVc=; h=From:To:Subject:In-Reply-To:From; b=JmVpJHH1tKLyA7ol2rjlZhD8nJYK7LZeaAdSxsat67H6/Bwcy/sXwdYhBJtmaWbCU 1JZWhQzFRmAJQCq6emWw+eFP9BpzIbJiejq3EW9asrW5ZPgqmLVnuXN8W/NZiGqXcR TCkj6RUb0C8ZA2xF4lcOEsKbLmdQo6NlCvjR2YrI= From: Andrew Morton To: akpm@linux-foundation.org, david@redhat.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, osalvador@suse.de, songmuchun@bytedance.com, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 137/200] mm/page_alloc: speed up the iteration of max_order Message-ID: <20201215031125.G8qpfmqBw%akpm@linux-foundation.org> In-Reply-To: <20201214190237.a17b70ae14f129e2dca3d204@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Muchun Song Subject: mm/page_alloc: speed up the iteration of max_order When we free a page whose order is very close to MAX_ORDER and greater than pageblock_order, it wastes some CPU cycles to increase max_order to MAX_ORDER one by one and check the pageblock migratetype of that page repeatedly especially when MAX_ORDER is much larger than pageblock_order. We also should not be checking migratetype of buddy when "order == MAX_ORDER - 1" as the buddy pfn may be invalid, so adjust the condition. With the new check, we don't need the max_order check anymore, so we replace it. Also adjust max_order initialization so that it's lower by one than previously, which makes the code hopefully more clear. Link: https://lkml.kernel.org/r/20201204155109.55451-1-songmuchun@bytedance.com Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") Signed-off-by: Muchun Song Acked-by: Vlastimil Babka Reviewed-by: Oscar Salvador Reviewed-by: David Hildenbrand Signed-off-by: Andrew Morton --- mm/page_alloc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/mm/page_alloc.c~mm-page_alloc-speeding-up-the-iteration-of-max_order +++ a/mm/page_alloc.c @@ -996,7 +996,7 @@ static inline void __free_one_page(struc struct page *buddy; bool to_tail; - max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1); + max_order = min_t(unsigned int, MAX_ORDER - 1, pageblock_order); VM_BUG_ON(!zone_is_initialized(zone)); VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); @@ -1009,7 +1009,7 @@ static inline void __free_one_page(struc VM_BUG_ON_PAGE(bad_range(zone, page), page); continue_merging: - while (order < max_order - 1) { + while (order < max_order) { if (compaction_capture(capc, page, order, migratetype)) { __mod_zone_freepage_state(zone, -(1 << order), migratetype); @@ -1035,7 +1035,7 @@ continue_merging: pfn = combined_pfn; order++; } - if (max_order < MAX_ORDER) { + if (order < MAX_ORDER - 1) { /* If we are here, it means order is >= pageblock_order. * We want to prevent merge between freepages on isolate * pageblock and normal pageblock. Without this, pageblock @@ -1056,7 +1056,7 @@ continue_merging: is_migrate_isolate(buddy_mt))) goto done_merging; } - max_order++; + max_order = order + 1; goto continue_merging; } _